Bore up and barrel length on an AUG

[outrider]

I have searched this and came up with conflicting results.

I have an AUG that has been upgraded with a bore up kit. I also have a 650mm tight bore inner barrel for it. It seems that no matter what size spring I put in the mech box I can't get more then 320 FPS.

I own two AUG's so I have the ability to mix and match parts. Here is what I have tried.

I have tried a regular length barrel and get around 400 FPS.
I have tried switching hop-ups and the results are the same.

I think my problem is that I am getting suck back on the inner barrel. I have read two different posts that conflict on how long a barrel a bore up kit will support.

I don't want to go out and buy a new 590mm barrel and find out it does not work either.

What length of inner barrel will an AUG bore-up kit support?

Thanks in advance.

[tsuru]

The easiest way to find out what length of barrel your bore-up kit will support is to put some tape on the bottom of your cylinder then fill it with water. (This is assuming it's a full cylinder without a port but then again that would run against the idea of a bore-up) This represents the maximum amount of air that can be held in the cylinder for a single shot. Now do the same thing to your barrel. If the amount of water that your barrel holds is more than the volume your cylinder can hold, there is your problem. If you want to find out how long a barrel your cylinder can support measure the water from the cylinder. Now measure the amount of water from your barrel. By dividing the amount of water the barrel supports by the length you have a ml/mm measurement. You can then compare versus your cylinder measurement and find out the maximum length your cylinder can support.

[Mantelope]

What's the strongest spring you've tried? Systema says that their bore-up kits won't work reliably with anything weaker than an M130.

[ILLusion]

Originally Posted by Mantelope

What's the strongest spring you've tried? Systema says that their bore-up kits won't work reliably with anything weaker than an M130.

Correction: M120.

(Their site is down right now, I can't get you the exact quote, but it will repeat the same thing in the Bore-Up Kit installation guide.)

[Mantelope]

Crap.

[outrider]

I installed a madbull M130 spring which is supposed to generate around 440 FPS.

I have also installed tork-up gears so I don't have to worry as much about burning out motors.

[outrider]

Originally Posted by tsuru

The easiest way to find out what length of barrel your bore-up kit will support is to put some tape on the bottom of your cylinder then fill it with water. (This is assuming it's a full cylinder without a port but then again that would run against the idea of a bore-up) This represents the maximum amount of air that can be held in the cylinder for a single shot. Now do the same thing to your barrel. If the amount of water that your barrel holds is more than the volume your cylinder can hold, there is your problem. If you want to find out how long a barrel your cylinder can support measure the water from the cylinder. Now measure the amount of water from your barrel. By dividing the amount of water the barrel supports by the length you have a ml/mm measurement. You can then compare versus your cylinder measurement and find out the maximum length your cylinder can support.

I was going to buy a caliper and measure the ID of the cylinder and the ID of the barrel (should be 6.03mm) and do the math. I also want to compare the ID of the bore up cylinder with the ID of the stock cylinder and see what the difference in ID is if any.

[Lethal_Bullet]

Originally Posted by outrider

I have searched this and came up with conflicting results.

I have an AUG that has been upgraded with a bore up kit. I also have a 650mm tight bore inner barrel for it. It seems that no matter what size spring I put in the mech box I can't get more then 320 FPS.

I own two AUG's so I have the ability to mix and match parts. Here is what I have tried.

I have tried a regular length barrel and get around 400 FPS.
I have tried switching hop-ups and the results are the same.

I think my problem is that I am getting suck back on the inner barrel. I have read two different posts that conflict on how long a barrel a bore up kit will support.

I don't want to go out and buy a new 590mm barrel and find out it does not work either.

What length of inner barrel will an AUG bore-up kit support?

Thanks in advance.

Quick Sidepoint:

How is your 650mm barrel fitted? Normall barrel and a long suppressor? Did you buy a longer barrel or make one. Trying to gather toghether an AUG Hbar but the three retailers I have found have ended their products permanently I dont have the tools to make one so I'm kinda stuck.

Any help/info apreciated,
Lethal(Dublin, Ireland)